World Wind is a free and open source (released under the NOSA license) virtual globe developed by NASA and the open source community for use on personal computers. Old versions need Microsoft Windows but the more recent Java version, World Wind Java, is cross platform and provides a suite of demo apps. The World Wind Java version was awarded NASA Software of the Year for 2009. The program overlays NASA and USGS satellite imagery, aerial photography, topographic maps and publicly available GIS data on 3D models of the Earth and other planets.